Alkyl-or arylsulfonyloxy,alkanoyloxy substituted propylphosphoric acid lower alkyl esters

ABSTRACT

A METHOD FOR THE PREPARATION OF ($) AND (-) (CIS1,2-EPOXYPROPYL) PHOSPHONIC ACID AND ITS CORRESPONDING SALTS AND ESTER DERIVATIVES WHICH COMPRISES TREATING A 1,2DISUBSTITUTED N-PROPYLYPHOSPHONIC ACID OR A SALT OR ESTER THEREOF UNDER RING CLOSURE CONDITIONS, AT LEAST ONE OF WHICH SUBSTITUENTS IS HYDROXY OR A FUNCTIONALLY EQUIVALENT OXYGEN-CONTAINING MOIETY AND THE REMAINING SUBSTITUENT BEING ANY LEAVING GROUP WHICH CAN BE DISPLACED TO YIELD THE DESIRED EPOXIDE PRODUCT. THE ($) AND (-) (CIS-1,2-EPOXYPROPYL)PHOSPHONIC ACID OF THIS IINVENTION AND ITS SALTS ARE ANTIBIOTICS WHICH HAVE UTILITY AS ANTIBACTERIALS IN INHIBITING THE GROWTH OF GRAM-POSITIVE AND GRAM-NEGATIVE PATHOGENIC BACTERIA.

United States Patent cc 3,819,676 ALKYL- 0R ARYLSULFONYLOXY, ALKANOYL- OXY SUBSTITUTED PROPYLPHOSPHORIC ACID LOWER ALKYL ESTERS Burton G. Christensen and Peter I. Pollak, Scotch Plains, and Norman L. Wendler, Snmmit,,N.J., assignors to Merck & Co., Inc., Rahway, NJ.

No Drawing. Original application Apr. 25, 1969, Ser. lflo. 819,447, now abandoned. Divided and this application Jan. 12, 1972, Ser. No. 217,264

Int. Cl. C07c 143/68 US. Cl. 260-456 R 7 Claims ABSTRACT OF THE DISCLOSURE A method for the preparation of and (cis l,2-epoxypropyl)phosphonic acid and its corresponding salts and ester derivatives which comprises treating a 1,2- disubstituted n-propylphosphonic acid or a salt or ester thereof under ring closure conditions, at least one of which substituents is hydroxy or a functionally equivalent oxygen-containing moiety and the remaining substituent being any leaving group which can be displaced to yield the desired epoxide product.

The (i) and (cis-l,2-epoxypropyl)phosphonic acid of this invention and its salts are antibiotics which have utility as antibacterials in inhibiting the growth of gram-positive and gram-negative pathogenic bacteria.

This is a division of application Ser. No. 819,447 filed Apr. 25, 1969, now abandoned.

This invention relates to a novel method for the preparation of (i) and (cis-l,2-epoxypropyl) phosphonic acid and the salts and ester derivatives thereof via the ring closure of a 1,2-disubstituted n-propylphosphonic acid.

The (i) and (cis-l,2-epoxypropyl) phosphonic acid product of the instant process and its salts are antibacterial agents, which are useful in inhibitingthe growth of both gram-positive and gram-negative pathogenic bacteria. The form of the product, and particularly its salts such as the sodium and calcium salts, is active against Bacillus, Escherichia, Staphylococci, Salmonella and Proteus pathogens, and antibiotic-resistant strains thereof. Illustrative of such pathogens are Bacillus subtilis, Escherichia coli, Salmonella schottmuelleri, Salmonella gallinarum, Salmonella pullorum, Proteus vulgaris, Proteus mirabilis, Proteus morganii, Staphylococcus aureus and Staphylococcus pyogenes. Thus, (1) and (cis-1,2-epoxypropyl) phosphonic acid and its salts can be used as antiseptic agents to remove susceptible organisms from pharmaceutical, dental and medical equipment and can also be used in other areas subject to in" fection by such organisms. Similarly, they can be used to separate certain microorganisms from mixtures of microorganisms. The salts of (cis-l,2-epoxypropyl) phosphonic acid are particularly valuable because not only do they have application in the treatment of diseases caused by bacterial-infections in man and animals but they are active against resistant strains of pathogens. The

said salts constitute .a preferred embodiment of this in- 3,819,676 Patented June 25, 1974 wherein the two R radicals may be the same or different and represent hydrogen, lower alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and the like, lower alkenyl such as allyl and like, mononuclear aryl such as phenyl or mononuclear aralkyl such as benzyl, phenethyl and the like and, when R is hydrogen, salts of the resulting acid, for example, those salts derived from the metals in Groups Ia, IIa, Ib and IIb of the Periodic System such as the alkali metal and alkaline earth metal salts, for example, the monoand disodium salts, the monoand di-potassium salts, the monoand di-silver salts and the calcium, magnesium and cadmium salts and amine salts such as those derived from alpha-phenethylamine, quinine, brucine, lysine, protamine, arginine, procaine, ethanolamine, morphine, benzylamine, ethylenediamine, N,N'-dibenzylethylenediamine, glycine, and the like and salts derived from such biologically active amides as tetracycline and novobiocin; and X and X are hydroxy, halo, for example, chloro, bromo, iodo and the like, azido, lower alkanoyloxy, for example, acetoxy, propionyloxy and the like, tn'halomethyl substituted lower alkanoyloxy such as trichloroacetoxy, trifiuoroacetoxy, 3,3,3 trifluoropropionyloxy, 3,3,3-trichloropropionyloxy and the like, hydrocarbylsulfonyloxy such as lower alkanesulfonyloxy, for example, methanesulfonyloxy, ethanesulfonyloxy and the like, arylsulfonyloxy, for example, phenylsulfonyloxy and the like, alkarylsulfonyloxy, for example, tolylsulfonyloxy and the like, aralkylsulfonyloxy, for example, benzenesulfonyloxy and the like, aroyloxy, for example, benzoyloxy, 4-toluyloxy, Z-naphthoyloxy and the like, aralkanoyloxy, for example, benzylcarbonyloxy, naphthylcarbonyloxy and the like, tri-lower alkylammonium, for example, trimethylammonium, tri-ethylammonium and the like, N-cycloalkyl di-lower alkyl-ammonium wherein the cycloalkyl radical is mono-nuclear cycloalkyl containing 5-6 nuclear carbon atoms such as cycIopentyl, cyclohexyl and the like, and di-lower alkylsulfonium, for example, dimethylsulfonium, diethylsulfonium, di-n-butylsulfonium and the like, aryloxy, for example, phenoxy and the like, aralkoxy, for example, benzyloxy and the like, dialkoxyphosphino, for example, di-lower alkoxyphosphino such as diethoxyphosphino and the like, N-(alkanesulfonyl)alkylamino or N-(alkarylsulfonyl)cycloalkylamino wherein the cycloalkyl radical is mononuclear cycloalkyl containing from 5-6 nuclear carbon atoms, for example, N-(p-toluenesulfonyl)cyclohexylamino and the like, at least one of which X and X radicals is hydroxy or other functionally equivalent oxygen-containing radical as, for example, an acyloxy group such as lower alkanoyloxy, trihalomethyl substituted lower alkanoyloxy, aroyloxy or aralkanoyloxy and the like, which, under ring closure conditions, will form the desired epoxide ring.

In addition to the pharmacologically acceptable metal and amine salts of (cis-l,2-epoxypropyl)phosphonic acid described above, this invention also includes other salts of the said acid inasmuch as those derivatives can be used as intermediates in synthesizing the free (cis-l,2-epoxy propyl)-phosphonic acid and its pharmacologically acceptable salts by metathesis. Furthermore, the salt of any optically active amine is within the scope of this invention inasmuch as it has utility as an intermediate in resolving racemic (cis-1,2-epoxypropyl)phosphonic acid into its optically active stereoisomers. Thus, for example, (cis l,Z-epoxypropyl)phosphonic acid may be resolved into its and enantiomers via the formation of a salt with an optically active amine salt by separation of the diastereoisomers of the said salt and regeneration of the and enantiomers of (cis-1,2-epoxypropyl) phosphonic acid.

Also, if desired, the (cis-l,2-epoxypropyl)phosphonic acid obtained via the foregoing method or any suitably esterified derivative thereof, may be converted to the antibacterially active (cis-l,2-epoxypropyl)phosphonic acid or its corresponding ester via treatment of the said stereoisomer with a reagent capable of cleaving the epoxide ring as, for example, with a suitable loweralkanoic acid or polyfiuorosubstituted lower-alkanoic acid, to alford the corresponding threo [l-hydroxy-2(acyloxy) propyl]phosphonic acid or its ester counterpart, which intermediate is then treated with a lower-alkanesulfonyl halide such as methanesulfonyl chloride followed by the conversion of the threo [l lower-alkanesulfonyloxy-Z (acyloxy)propyl]phosphonic acid or corresponding phosphonate thus obtained to the desired stereoisomer via the method of this invention. The choice of a suitable reagent for cleaving the epoxide nucleus is determined largely by the character of the epoxide reactant; thus, for example, when the reactant is (cis-l,2-epoxypropyl) phosphonic acid cleavage is most advantageously conducted with a lower-alkanoic acid such as acetic acid, whereas, when an ester derivative of (cis-l,2-epxypropyl)phosphonic acid is the reactant employed cleavage is most conveniently effected via the use of formic acid or a polyfluoro substitued lower-alkanoic acid such as trifluoroacetic acid and the like. This method for the conversion of inactive (cis-1,2-epoxypropyl)phosphonic acid or an ester thereof to the corresponding stereoisomer constitutes a preferred aspect of this invention and is more precisely illustrated by reference to the specific examples comprising this specification.

Since the ring carbons in the (cis 1,2-epoxypropyl) phosphonic acid (I) are asymmetric carbons (starred, supra) it follows that the product (I) may exist as one or more of four optically active isomers as shown by the following formulae:

0 O O H NORM (RO)zI H (RO)21 H a a a H cn, nae- 41 H on.

lS:2R cia 1R:2S cia 1R:2R trans O T H P(OR);

it H O H 18:28 tram Of the four isomers the 1R:2S, i.e., (cis-1,2-epoxypropyl)phosphonic acid, has proved to be most effective in inhibiting the growth of pathogenic bacteria and, therefore, the preparation of that particular derivative constitutes a preferred embodiment of this invention. To effect the synthesis of that isomer or any other isomeric derivative, it is only necessary to select as the reactant in the process the appropriately resolved starting material.

In principle the instant process proceeds via an intramolecular displacement of the X or X substituents attached to the asymmetric carbons of the phosphonic acid reactant (II) by the neighboring oxygen substituent. As a consequence, the process results in a net inversion of the starting material configuration at one or the other of the said asymmetric ceners depending largely upon the character of the X and X substituents attached to the alkylene chain of the n-propylphosphonic acid starting material (II). This inversion of configuration is best illustrated by the following formulae which show the two asymmetric carbons in the reactants (II) to be so oriented that they lie in the projection plane and the hydrogen and X and X moieties are above or below the said plane. Also, because of the two asymmetric carbons the reactants can be represented as two series of compounds containing two pairs of enantiomeric diastereoisomers in each series. Thus, in the A series, infra, the oxygen-containing radical is bonded to the 2-carbon in the n-propylphosphonic acid molecule and there exists in that series two pairs of enantiomeric diastereoisomers, i.e., the 1R:2S erythro and lS:2R erythro enantiomers on the one hand and the 18:25 threo and 1R:2R threa onthe other, with each pair of enantiomers having identical physical and chemical properties except for the direction in which they rotate the plane of polarized light. Similarly, in series B, infra, where the oxygen-containing moiety is bonded to the l-carbon of the n-propylphosphonic acid reactant there exist two pairs of enantiomers, i.e., the 1R:2S erythro and lS:2R erythro isomers and the 18:28 three and 1R:2R threo isomers. For purposes of illustration the following formulae depict the oxygen-containing radical as an O moiety; however, this is for illustration only and it will be obvious to those skilled in the art that in fact the said moiety may be any one of the oxygen-containing substituents cited above in respect of the definition of X and X T a P (on) 2 wherein 0 R, X and X are as defined above.

Epoxide formation is effected (l) by treating the 1,2- disubstituted n-propylphosphonic acid starting material (II) with a suitable acid such as sulfuric acid, peracetic acid or nitrous acid and the like or with a Lewis Acid such as boron trifluoride or phosphorous pentoxide and the like or with hexafluoroacetone in the presence of a suitable protonic acid such as para-toluenesulfonic acid or a mineral acid such as sulfuric or hydrochloric acid and the like or (2) with a solution of an ionizable metal in a neutral or acidic solution as, for example, with silver acetate in a mineral acid such as hydrochloric acid and the like or (3) by treatment with a base having a pH equal to or greater than 7; suitable bases include, for example, alkali metal or alkaline earth metal hydroxides such as sodium. hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, etc. alkaline metal or alkaline earth metal carbonates or bicarbonates such as sodium carbonate, potassium carbonate, calcium carbonate, sodium bicarbonate, potassium bicarbonate, etc., basic metal oxides such as sodium oxide, potassium oxide, calcium oxide, cadmium oxide, gold oxide, silver oxide, etc., tertiary organic bases, for example, tertiary alkylamines such as trimethylamine, triethylamine, pyridine, etc., quaternary ammonium bases, for example, trilower alkylammonium alkoxides such as trimethylammonium methoxide, triethylammonium ethoxide, etc., alkali metal or alkaline earth metal alkoxides such as sodium methoxide, sodium ethoxide, potassium ethoxide, potassium tertiary-butoxide and the like or Lewis bases in aprotic solvents such as peroxide ion in acetonitrile or (4) by passing a solution of the starting material through an ion-exchange column on the basic cycle. When an optically active starting material selected from the series A or B, supra, is subjected to epoxide formation in an alkaline, acid or neutral medium the reaction proceeds with a net inversion of the configuration at the carbon atom bearing the leaving substituent X or X Thus, when it is desired to obtain the optically active 1R:2S erythro (cis-1,2-epoxypropyl)phosphonic acid isomer it is only necessary to select as the starting material the 18:28 threo precursor in the A series (supra) or the 1R:2R threo precursor in the B series (supra) since those isomers will, upon inversion, yield the desired 1R:2S erythro product. The result is a process proceeding with a net single inversion of configuration at the carbon atom bearing the leaving group X or X The following equation wherein the starting material is a 15:28 threo-Z-hydroxy substituted n-propylphosphonic acid or a salt or ester derivative thereof (Ila, infra) illustrates this reaction; however, it is to be understood that the corresponding 1R:2R threo-l-hydroxy substituted npropylphosphonic acid isomer or any other functionally equivalent oxygen-containing reactant may be substituted therefor in an otherwise analogous reaction to yield an identical 1R:2S erythro product (Ia, infra) and, if desired, any other isomeric derivative or a racemic mixture of isomers may be employed to yield the correspondingly inverted or racemic product:

18 :28 three (11a) 0 (R O; H

1R:2S cis (Ia) Inversion wherein R and X are as defined above and, when R in the starting material (11a) is hydrogen, the product (la) is obtained in the form of the corresponding salt.

Also, in addition to a single step inversion this invention includes syntheses of two steps or more in which the 1,2-disubstituted n-propylphosphonic acid reactant may be prepared in situ and the precursor thus obtained can be converted to the desired epoxide product (I) via the instant process. Thus, for example, in the preparation of the instant l(2)-hydroxy-2(1)-halo-substituted-npropylphosphonic acid starting materials a 1(2)-hydroxy- 2(l)-chloro-n-propylphosphonic acid may be first synthesized as an initial intermediate and the precursor thus obtained can be converted to its corresponding 1(2)-hydroxy-2(1)-iodo-n-propylphosphonic acid analog and the latter intermediate converted to the desired (cits-1,2- epoxypropyl)phosphonic acid product (1) according to the process of this invention.

The 1,2-disubstituted n-propylphosphonic acid reactants (II) of the instant process and the salts and ester derivatives thereof are conveniently obtained by several alternate routes. One such method of preparation and one which is suitable for preparing those reactants wherein the oxygen-containing moiety is bonded to the l-carbon of the n-propylphosphonic acid molecule, comprises treating phosphorous acid or a salt or ester of phosphorous acid with a propionaldehyde which is substituted at the 2-carbon by an appropriate leaving group (III, infra). The following equation illustrates this method of preparation:

0 O T T CHaCHX -CHO H P (O R) 2 CH CHX -CHP (O R):

(III) (III!) wherein R and X are as defined above. Alternatively, in lieu of a propionaldehyde and the phosphorous acid derivatives described above the [l-hydroxy-2-(X -substituted)-n-propyl]phosphonic acid derivatives may be obtained via the reaction of a suitably substituted propionyl halide with a phosphite and the (LX -substituted propionyl)phosphonate thus obtained is reduced as, for example, by treatment with an alkali metal borohydride such as sodium borohydride to yield the desired [l-hydroxy-Z-(X -substituted)-n-propyl phosphonic] acid derivative. The 1,2-disubstituted n-propylphosphonic acid (IIb) or its salt or ester derivative thus obtained may be used directly as the starting material in the process of this invention or, if desired, the said [l-hydroxy-2-(X substituted)n-propyl]phosphonic acid (IIb) may be treated with a suitable esterifying agent as, for example, with an alkanoyl halide, trihalomethyl substituted lower alkanoyl halide, aroyl halide, aralkanoyl halide, lower alkanesulfonyl halide, etc. to yield the corresponding [1- acyloxy-2-(X -substituted)n-propyllphosphonic acid or l-lower alkanesulfonyloxy-2(X -substituted)n-propyl] phosphonic acid or the salt and ester derivatives thereof. The following equation illustrates such a method for the preparation of a [l-lower alkanesulfonyloxy-Z-(X. -substituted)n-propyl]phosphonic acid derivative via the reaction of the corresponding [l-hydroxy-2-(X -substituted)n-propyl]phosphonic acid (IIb) with a lower alkanesulfonyl halide; however, it isto be understood that the equation is illustrative only and that the other corresponding [1 acyloxy-2-(K -substituted)n-propyl] phosphonic acid analogs thereof and their salts and esters may also be obtained in an analogous manner simply by substituting the appropriate acyl halide for the lower alkanesulfonyl halide described as the starting material therein:

wherein R is lower alkyl such as methyl, ethyl, n-propyl, etc., aryl such as phenyl, tolyl and the like or aralkyl such as benzyl; Z is halo, for example, chloro, bromo, fluoro, and the like and R and X are as defined above.

The (l-hydroxy-2-sulfonyloxypropyl)phosphonic acid starting materials may be prepared by treating an appropriately substituted 2-sulfonyloxypropionyl halide with a phosphite, followed by the reaction of the resulting (2- sulfonyloxypropionyl)phosphonate intermediate thus obtained with a suitable reducing agent such as sodium borowherein X is halo such as chloro, bromo and the like and R and R are as defined above. The 2-sulfonylpropionyl halides employed as starting materials in the foregoing process are conveniently obtained via the reaction of a lactic acid ester with an appropriate sulfonyl halide followed by the halogenation of the 2-sulfonyloxypropionate intermediate thus obtained to the desired 2-sulfonyloxypropionyl halide.

Those 1,2-disubstituted n-propylphosphonic acid derivatives wherein a dialkylsulfonium radical is bonded to the 2-carbon of the n-propylphosphonic acid moiety (IIe, infra) are conveniently obtained by treating a [l-hydroxy- 2-(alkylthio)propylJphosphonate ("IId, infra) with an alkyl halide. The following equation illustrates this method of preparation, including the step of synthesizing the l-hydroxy 2 (alkylthio)propyl]phosphonate intermediate (IId) via the aforedescribed method of treating a suitably substituted propionaldehyde (.IIIa, infra) with phosphorus acid or with the corresponding phosphite derivative:

o H3-oH- CH-I (oR)2 Z l ma H wherein R is lower alkyl such as methyl, ethyl, n-propyl and the like, R Z is a lower alkyl halide such as methyl iodide, methyl fluoride, ethyl iodide, ethyl chloride, ethyl bromide, n-propyl iodide etc., Z is the anion derived from halogen such as chloro, bromo, fluoro or iodo and R is as defined above.

Alternatively, those 1,2 disubstituted n propylphosphonic acids reactants wherein the sulfonium radical is bonded to the l-carbon of the n-propylphosphonic acid (Hg, infra) may be obtained by treating (l-propenyl) phosphonic acid or a salt or ester thereof with a sulfenyl halide, followed by the reaction of the [(l-phosphinyl) 1,2-propylene]-alkylsulfonium halide intermediate (IV, infra) thus obtained with the metal salt of an alkanoic acid to yield the corresponding ['l-(alkylthio)-2-alkanoyloxypropylJphosphonic acid or phosphonate derivative thereof -(IIf, infra) which is then treated with an alkyl halide to yield the desired [1-hydroxy-2-'(dialkylsulfonium)propyl]phosphonic acid (Hg). The following equation illustrates this method of preparation:

Z in

R COOM l T CHr-CH-CH-P (OR);

INC 0 S R (IIf) R X l CHr-CH-(JH-i OR OH s mmx wherein R X is a lower alkyl halide such as methyl iodide, ethyl iodide, n-propyl iodide, n-butyl iodide, methyl chloride, n-propyl chloride, etc.; R SZ is a lower alkylsulfenyl halide such as n-butylsulfenyl chloride and the like; R is lower alkyl such as methyl, ethyl, n-propyl, n-butyl, etc.; R COOM is the metal salt of a lower alkanoic acid such as silver acetate sodium n-propionate, silver n-butyrate, etc.; X is the anion derived from halogen such as chloro, bromo, fluoro or iodo; and R, R Z and Z are as defined above.

Still another method by which the 1,2-disubstituted npropylphosphonic acid reactants (II) may be synthesized and one which is suitable for preparing those derivatives wherein an oxygen-containing radical is bonded to the 2- carbon of the n-propylphosphonic acid molecule (IIh, infra) comprises treating l-propenylphosphonic acid or a salt or ester thereof (V, infra) with a reagent which will 'add an oxygen-containing moiety and a leaving group across the vinylene double bond of the l-propenyl radical. Whether the reaction proceeds by direct addition or via a multi-step synthesis depends largely upon the character of the oxygen-containing substituent and the leaving group in the 1,2-disubstituted n-propylphosphonic acid compound. For example, any 1,2-disubstituted n-propylphosphonic acid wherein the oxygen-containing substituents are hydroxy and an alkanoyloxy or trihalomethyl substituted alkanoyloxy may be prepared simply by treating the 1- propenylphosphonic acid or a salt or ester thereof with an alkanoic peracid and anhydrous mineral acid or with an appropriate trihalomethyl substituted alkanoic acid in the presence of a peracid such as perbenzo'ic acid. Also, in the equation which follows both the hydroxy radical and the alkanoyloxy and trihalomethylalkanoyloxy moieties function as oxygen-containing substituents; therefore, the instant process constitutes an effective method for the preparation of starting materials which may contain up to two oxygen-containing moieties in the n-propylphosphonic acid molecule and, when the said reactant contains only one such oxygen-containing moiety, that radical is bonded to the 2-carbon of the said acid:

0 CHa-CH-H-MORM R 0 0 OH rm) wherein R is lower alkyl such as methyl, ethyl, etc., trihalomethyl such as trifluoromethyl, trichloromethyl, etc., or trihalomethyl substituted lower alkyl such as 2,2,2-trifluoroethyl, 2,2,2 trichloroethyl, etc., and R is as defined above.

When the leaving group in the 1,2-disubstituted n-propylphosphonic acid reactant (II) is halogen and the oxygen-containing substitutent is attached to the Z-carbon, the said halohydrin-type starting material can be obtained by treating a l-propenylphosphonate with an aqueous solution of an halogenating agent. The following equation wherein the reagents employed are n-bromosuccinimide and aqueous sulfuric acid illustrates this process; however, it will be obvious to one skilled in the art that other functionally equivalent halogenating agents can be substituted therefor in an otherwise analogous process to yield the corresponding (l-halo-Z-hydroxypropyl)phosphonate derivative (Hi, infra):

a cation derived from an alkali metal or alkaline earth metal.

Still another method for the preparation of the chlorohydrin starting materials and one which is particularly suitable for the preparation of the (i) threo (l-halo-Z- hydroxypropyl)phosphonic acid series of reactants (IIj, infra) comprises treating a cis-l-propenyl phosphonic acid with a solution of a hypohalite. The (i) threo (1-halo-2- hydroxypropyl)phosphonic acid derivative (Ilj), thus obtained can then either be isolated to be used per se as a starting material in the process of this invention or, if desired, the said (i) chlorohydrin (IIj) may be subjected to resolution to afford the threo (1-halo-2-hy droxypropyl)phosphonic acid isomer (IIm, infra) which,

upon ring closure according to the method of this invention aifords (cis-1,2-epoxypropyl)phosphonic acid or the salt or ester derivative thereof. The following equations illustrate this method of preparation; equation (1) describes the method by which (i) threo (l-halo-2-hydroxypropyl)phosphonic acid (IIj) may be obtained via the treatment of cis-l-propenyl phosphonic acid with a solution of a hypohalite and equation (2) describes the method by which the racemic derivative (111') may be resolved via treatment with a suitable resolving agent to afford the corresponding salt (Hk, infra) which, upon passage through an ion exchange column on the hydrogen cycle aflords the desired threo (1-halo-2-hydroxypropyl)phosphonic acid derivative (IIm). It will be noted in equation (2) that the resolving agent employed is -alpha-phenethylamine; however, it should be apparent to those skilled in the art that other functionally equivalent reagents may be substituted therefor to afford an identical threo (1-halo-2-hydroxypropyl)phosphonic acid derivative (Hm).

2 T alpha-phenethylamine CH --CH-CHP(0H)2 9 6B O OHsN-CH T/ I ll CH -CHCHP CH;

H X4 OH (H Ion Exchange 2 r-CHCHP(OH),

wherein X is a halo moiety, for example, .chloro, bromo or iodo and the like. Suitable hypohalite solutions which may be employed in the preparation of the threo (l-halo- 2-hydroxypropyl)phosphonic acid intermediate (Ilj) include, for example, the alkali metal hypohalites and lower alkyl hypohalites as, for example, sodium and potassium hypochlorite and the like or tertiary-butyl hypochlorite and the like.

Those 1,2-disubstituted n-propylphosphonic acid reactants wherein the leaving group is a substituted amino radical and the oxygen-containing substituent is attached to the 2-carbon of the n-propylphosphonic acid molecule (IIn, infra) are prepared via the reaction of a l-propenylphosphonate with a suitable halogenating agent such as bromine in chloroform in the presence of a suitable primary amine and the (l-primary-amino-Z-methyl-3-aziridinyl)-phosphonate intermediate (VI, infra) thus obtained is then hydrolyzed by treatment with an aqueous solution of an acid to yield the desired [l-(primary 10 amino)-2-hydroxypropyl]-phosphonate (IIn). The following equation illustrates this method of preparation:

orn-oH-on-P 0 R wherein R is alkyl or mononuclear cycloalkyl such as cyclopentyl, cyclohexyl, etc., X is a halogenating agent such as chlorine, bromine, etc. and H is the cation derived from an organic or inorganic acid such as paratoluenesnlfonic acid, hydrochloric acid, sulfuric acid, and the like. Alternatively, in lieu of treating the (l-primary-amino- 2-methyl-3-aziridinyl)phosphonate intermediate (VI) of the foregoing method, with an aqueous solution of an acid, the said intermediate (VI) can be treated with the alkali metal salt of a suitable alkanoic acid, as for example, with sodium acetate, in an acidic medium to afford the corresponding [l-(primary-amino)-2-alkanoyloxypropyl]phosphonate (VII, infra), which intermediate can then be treated with an appropriate sulfonyl halide in a suitable solvent such as pyridine to yield the desired [1- N- (hydrocarbylsulfonyl -primary-amino] -2-alkanoyloxypropyl]phosphonate (IIp, infra). The following equation wherein the sulfonyl halide reagent employed is ptoluenesulfonyl chloride illustrates this method of preparation: g Q

CH3-CHCHP 01m R80 0 OM OH3-CH-CH-1T3 on III R 0 NHR u (VII) 45 (VI) CHsQ-S 02011 0 5 CHsCH-TH- R):

R30 01) N-S OQ-Q-Cm wherein R, R COOM and R are as defined above.

The (cis 1,2 epoxypropyl)phosphonic acid referred to herein rotates plane-polarized light in a counterclockwise direction (to the left as viewed by the observer) when the rotation of its disodium salt is measured in water (5% concentration) at 405 III/L.

The designation cis used in describing the 1,2-epoxypropylphosphonic acid compounds means that each of the hydrogen atoms attached to carbon atoms 1 and 2 of the propylphosphonic acid are on the same side of the oxide ring.

The following examples illustrate the method by which (cis-1,2-expoxypropyl)phosphonic acid and its salts and ester derivatives (I) may be obtained. However, the examples are illustrative only and should not be construed as being limited thereto since other functionally equivalent reagents may be substituted for the reagents recited therein to yield an identical (cis-l,2-epoxypropyl) phosphonic acid product and its corresponding salts and ester derivatives.

(Cis-1,2,-epoxypropyl)phosphonic acid, dimethyl ester and disodium salt Step A: T hreo dimethyl (l-hydroxy-Z-chloropropyl)- phosphonate.-2-Chloropropionaldehyde mmoles) is added to dimethyl phosphite (5 mmoles) and the reaction mixture warmed to 50-60 C. After a period of 24 hours, the reaction product is fractionated to yield threo dimethyl l-hydroxy-Z-chloropropyl)phosphonate.

Step B: Dimethyl (cis-l,2,-epoxypropyl)phosphonate. A solution of threo dimethyl (l-hydroxy-Z-chloropropyl) phosphonate (0.124 g.) in methanol (2 cc.) is titrated with 1.08 N sodium hydroxide (0.5 cc.) using phenolphthalein as the indicator. The total amount of base consumed is 0.5 cc. Upon evaporation of the methanol at 25 C. and extraction of the residue with ether the solution yields upon concentration of the ether in vacuo, a product identified as dimethyl (cis-LZ-epoxypropyl) phosphonate.

Step C: (Cis-1,2,-epoxypropyl)phosphonic acid and disodium salt.A solution of dimethyl (cis-1,2,-epoxpyropyl)phosphonate (l mmole) in trimethylchlorosilane cc.) is refluxed for eight hours. The reaction mixture is then extracted with water to yield an aqueous solution of (cis-l,2,-epoxypropyl)phosphonic acid and the said product is then treated with two equivalents of sodium hydroxide and the solution evaporated to yield disodium (cis-1,2-epoxypropyl)phosphonate.

By substituting diallyl phosphite for the dimethyl phosphite recited in Example 1, Step A, and following the procedure described therein the intermediate threo diallyl (l-hydroxy-2-chloropropyl)phosphonate obtained, which upon treatment with sodium hydroxide according to the method described in Example 1, Step B, yields diallyl (cis- 1,2-epoxypropyl)phosphonate. The diallyl ester thus obtained can then be subjected to hydrogenolysis or treated with trimethylchlorosilane and with lithium hydroxide according to the method described in Example 1, Step C, to yield, respectively, an aqueous solution of (cis-l,2-epoxypropyl)phosphonic acid and dilithium (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 2 Diethyl (Cis-1,2-epoxypropy1)phosphonate Step A: Threo diethyl (l-hydroxy-2-acetoxypropyl) phosphonate.A solution of 2-acetoxypropionaldehyde (5 mmoles) in 'benzene (5 cc.) is treated with diethyl phosphite (5 mmoles) and two drops of triethylamine. After a period of hours, benzene is added and the organic solution is washed with dilute hydrochloric acid and then with water and dried over magnesium sulfate. Evaporation of the solvent followed by distillation of the residue yields threo diethyl (1-hydroxy-2-acetoxypropyl) phosphonate.

Step B: Threo diethyl [l-(methanesulfonyloxy)-2- acetoxypropyl]phosphonate.--Threo diethyl (l-hydroxy- 2-acetoxypropyl)phosphonate (2 mmoles) is dissolved in pyridine (10 cc.) and the solution treated with 1.1 equivalents of methanesulfonyl chloride and allowed to stand for 12 hours at room temperature. At the end of the 12- hour period, the pyridine is evaporated in vacuo and the residue dissolved in ether and the ether solution washed with water, dried and evaporated to yield crude diethyl 1- (methanesulfonyloxy) -2-acetoxypropyl] phosphonate.

Step C: Diethyl (cis-1,2-epoxypropyl) phosph0nate.A solution of diethyl [l-(methanesulfonyloxy)-2-acetoxypropyl]phosphonate (1 mmole) in methanol (2 cc.) is titrated with 1 N sodium hydroxide using phenolphthalein as the indicator. The total amount of base consumed is 2.0 mmoles. Upon evaporation of the methanol at C., extraction of the residue with ether and concentration of the ether in vacuo, the product obtained is identified as diethyl (cis-l,2-epoxypropyl)phosphonate.

12 EXAMPLE 3 Dimethyl (cis-1,2-epoxypropyl)phosphonate Step A: Dimethyl [1-hydroxy-2-(methanesulfonyloxy) propyl]phosphonate-A solution of 2-hydroxypropionaldehyde (0.01 mole) in pyridine (10 cc.) is treated at 05 C. with methanesulfonyl chloride (0.012 mole) and allowed to stand for 18 hours at 0-5 C. The reaction mixture is then decomposed with ice and extracted with ether. The ether extract is washed free of pyridine with cold dilute hydrochloric acid and finally with a saturated salt solution and dried over magnesium sulfate. Evaporation of the solvent yields the mesylate ester of 2-hydroxypropionaldehyde and 5 mmoles of the product thu obtained is treated with dimethyl phosphite (5 mmoles) and warmed to 50-60 C. and allowed to stand for one day whereupon there is obtained threo dimethyl [l-hydroxy- 2- (methanesulfonyloxy) propyl] phosphonate.

Step B: Dimethyl (cis-1,2-epoxypropyl)phosphonate.- By substituting threo dimethyl [l-hydroxy-Z-(methanesulfonyloxy)propyl]phosphonate for the dimethyl [1- (methanesulfonyloxy) 2 acetoxypropyl]phosphonate of Example 2, Step C, and following the procedure described therein employing 1 milliequivalent of alkali the product dimethyl (cis-1,2-epoxypropyl)phosphonate is obtained.

EXAMPLE 4 Di-n-propyl (cis-l,2-epoxypropyl)phosphonate Step A: Threo di-n-propyl (l-hydroxy-Z-aminopropyl) phosphonate-A solution of 2-arninopropionaldehyde (5 mmoles) and di-n-propyl phosphite (5 mmoles) in benzene (5 cc.) is allowed to stand for 18 hours. The solvent is evaporated and the residue distilled to yield threo di-npropyl 1-hydroxy-2-aminopropyl) phosphonate.

Step B: 1-di-n-propyloxyphosphinyl)-1-hydroxy-2- propylJtrimethylammonium iodide-A solution of threo dim-propyl (1-hydroxy-2-aminopropyl)phosphonate (2 mmoles) in 20 cc. of methanol is treated with methyl iodide (10 mmoles) and 10% aqueous potassium hydroxide (12 mmoles) is added dropwise with stirring. The alcohol is evaporated and replaced with benzene which is evaporated to azeotrope the reaction mixture to dryness. The residue suspended in benzene (20 cc.) is treated with methyl iodide (10 mmoles) and refluxed for two hours. At the conclusion of the 2-hour period the reaction mixture is evaporated to dryness to yield [(l-di-n-propyloxyphosphinyl) 1 hydroxy 2 propyl]trimethylammonium iodide.

Step C: Di-n-propyl (cz's 1,2 epoxypropyl)phosphonate.-The [(1 di-n-propyloxyphosphinyl) -1 hydroxy-Z-propyl]trimethylammonium iodide obtained according to Step B is suspended in methanol and treated with freshly prepared silver oxide (50 mmoles). The reaction mixture is stirred for two hours at room temperature, filtered and the filtrate evaporated to dryness. The residue is dissolved in ether and the ether washed with 5% sodium bicarbonate solution, dried over magnesium sulfate, filtered and concentrated to yield di-n-propyl (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 5 Di-n-butyl (cis-1,2-epoxypropyl)phosphonate Step A: Threo di-n-butyl [1 hydroxy-2-(ethylthio)- propyl]phosphonate.2 (Ethylthio)propionaldehyde (5 mmoles) and di-n-butyl phosphite (5 mmoles) is treated with two drops of triethylamine and allowed to stand at 30 C. for 20 hours. The reaction mixture is warmed at 50-60 C. for one hour, cooled to room temperature, taken up in ether and the triethylamine removed by extraction with dilute hydrochloric acid. The washed ether solution is dried over magnesium sulfate, concentrated and the residue distilled under reduced pressure to yield threo di-n-butyl [1 hydroxy-2-(ethylthio)propyl]phosphonate.

Step B: Threo [(1-di-n-butyloxyphosphinyl) 1 hydroxy-2-propyl] diethylsulfonium iodide.-Di-n-butyl [1- hydroxy-Z-(ethylthio)propyl]phosphonate (3 mmoles) is dissolved in benzene and the solution treated with ethyl iodide l mmoles). The reaction mixture is then warmed at 80 C. for two hours and the benzene evaporated in vacuo to yield threo [(l-di-n-butyloxyphosphinyl)-l-hydroxy-2-propyl]-diethylsulfonium iodide.

Step C: Di-n-butyl (cisl,2-epoxypropyl)-phosphonate.-Threo [(1-di-n-butyloxyphosphinyl')-1-hydroxy-2- propyl]-diethylsulfonium iodide (3 mmoles) is dissolved in ethanol and the reaction mixture treated with silver oxide (5 mmoles) over a period of one-half hour. The essentially neutral reaction mixture is concentrated in vacuo and the residue taken up in ether. The ether solution is then washed with water, dried over sodium sulfate and concentrated to yield di-n-butyl (cis-1,2-epoxypropyl) phosphonate.

EXAMPLE 6 Disodium (Cir-1,2-epoxypropyl)phosphonate Step A: Threo-[l-hydroxy 2 (trichloroacetoxy)propyl]-phosphonic acid.A solution of cis-l-propenylphosphonic acid (0.05 mole), perbenzoic acid (0.06 mole) and trichloroacetic acid (0.06 mole) in benzene (100 cc.) is allowed to stand for two hours at 25 C. The reaction mixture is washed with dilute sodium carbonate solution, dried over magnesium sulfate and concentrated to yield three- [1 hydroxy-2-(trichloroacetoxy)propyl]phosphonic acid.

Step B: Pyridine salt of [l-(methanesulfonyloxy)-2-acetoxypropyl1phosphonic acid.Threo-[1-hydroxy 2 (trichloroacetoxy)propyl]phosphonic acid (2 mmoles) is dissolved in pyridine (10 cc.) and the solution treated with 1.1 equivalent of methanesulfonyl chloride and allowed to stand for 12 hours at room temperature. At the end of the 12-hour period the pyridine is evaporated in vacuo and the residue triturated with ether to yield crude pyridine salt of [1 (methanesulfonyloxy)-2-acetoxypropyl]phosphonic acid.

Step C: Disodium (cis-l,Z-epoxypropyl)phosphonate.- A solution of the pyridine salt of [l-(methanesulfonyloxy)-2-acetoxypropyl]phosphonic acid (1 mmole) in methanol (2 cc.) is titrated with four equivalents of 1 N sodium hydroxide using phenolphthalein as the indicator. Upon evaporation of the methanol at 25 C., extraction of the residue with ether and concentration of the ether in vacuo, the product obtained is identified as disodium (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 7 Dimethyl (cis-1,2-epoxypropyl)phosphonate Step A: Threo dimethyl (l-bromo-2-hydroxypropyl)- phosphonate.A solution of dimethyl cis-l-propenylphosphonate (5 mmoles) in water (12 cc.) is treated with N- bromosuccinimide (6 mmoles) at 0 C. followed by the addition of cold 0.2 N aqueous sulfuric acid (1.5 ml.). After stirring for a period of four to five hours at 0 C., excess N-bromosuccinirnide is destroyed by the addition of a few drops of sodium bisulfite solution. The aqueous solution is saturated with sodium chloride, extracted with ether, dried over magnesium sulfate and concentrated to yield threo dimethyl (l-bromo 2 hydroxypropyDphosphonate.

Step B: Dimethyl (cis-1,2-epoxypropyl)phosphonate. By substituting threo dimethyl (l-bromo-Z-hydroxypropyl)phosphonate for the threo diethyl [l-(methanesulfonyloxy)-2-acetoxypropyl]phosphonate of Example 2, Step B, and following the procedure described therein the product dimethyl (cis-1,2-epoxypropyl)phosphonate is obtained.

EXAMPLE 8 Three dimethyl (cis-l,2-epoxypropyl)phosphonate Step A: Dimethyl thre [l-(cyclohexylamino)-2-hydroxypropyl]phosphonate.- Bromine is added dropwise to a solution of dimethyl cis-l-propenylphosphonate (5 mmoles) in chloroform (25 cc.) at such a rate that the bromine absorption is matched by the rate of bromine addition. Upon completion of the bromine absorption the solvent is evaporated and the reaction mixture treated with a solution of cyclohexylamine (10 mmoles) in dry benzene (20 cc.) and allowed to stand for a six-hour period at 30 C. The reaction mixture is filtered from cyclohexylamine hydrobromide and the solvent evaporated to yield dimethyl (1-cyclohexyl-2-methyl-3-aziridinyl)phosphonate. The ester intermediate thus obtained is then dissolved in 2 N sulfuric acid at 40 C. to effect hydrolysis whereupon the compound dimethyl threo [l-(cyclohexylamino)-2-hydroxypropyl] phosphonate is obtained.

Step B: [(l-dimethoxyphosphinyD-2-hydroxy-2-propyl]- N-cyclohexyl dimethylammonium iodide-By substituting threo dimethyl [1-(cyclohexylamino)-2-hydroxypropyl] phosphonate for the threo di-n-propyl (l-hydroxy-Z- aminopropyl)phosphonate of Example 4, Step B and following the procedure described therein threo [(l-dimethoxy hosphinyl)-2-hydroxy-2-propyl] N cyclohexyl dimethylammonium iodide is obtained.

Step C: Dimethyl (cis-LZ-epoxypropyl)phosphonate. By substituting threo [(l-dimethoxyphosphinyl)-2-hydroxy-2-propyl]-N-cyclohexyl dimethylammonium iodide for the threo [(1-di-n-propyloxyphosphinyl)-l-hydroxy-2- propyl]trimethylammonium iodide of Example 4, Step C, and following the procedure described therein the product dimethyl (cis-l,2-epoxypropyl)phosphonate is obtained.

EXAMPLE 9 Dimethyl (cis-l,2-epoxypropyl)phosphonate Step A: T hreo dimethyl (1-hydroxy-2-aminopropyl)- phosphonate.A solution of earbobenzoxyalanine p-nitrophenyl ester (0.5 mmole) in 25 cc. of dimethyl formamide is treated with sodium dimethyl phosphonate (1.0 mmoles) in 10 cc. of dimethyl formamide and the mixture is warmed to 50 C. for one hour. The reaction mixture is then diluted with water and extracted with ether. The ether solution is concentrated, taken up in 25 cc. of methanol, treated with 50 mg. of 10% palladium on charcoal and hydrogenated to the uptake of 2 mole equivalents of hydrogen. The catalyst is removed by filtration and the solvent removed in vacuo to afford threo dimethyl l-hydroxy-Z-aminopropyl phosphonate.

Step B: Dimethyl (cis-1,2-epoxypropyl)phosphonate.-- A solution of 0.1 mmole of threo dimethyl (1-hydroxy- 2-aminopropyl)phosphonate in 50% aqueous acetic acid (15 cc.) is treated with 0.1 mmole of sodium nitrite dissolved in 5 cc. of water. After complete nitrogen evolution the organic product is extracted with ether and the ether solution washed with sodium bicarbonate solution, dried over sodium sulfate and concentrated to yield the dimethyl (cis-l,2-epoxypropyl)phosphonate.

EXAMPLE 10 Dimethyl (cis-1,2-epoxypropyl)phosphonate Step A: Threo dimethyl [l-(phenylimino)-2-hydroxypropyl]phosphonate.An equimolecul-ar mixture of dimethyl cis-l-propenylphosphonate and phenylazide are allowed to stand at 25 C. for 24 hours and then warmed until no further nitrogen is evolved. The dimethyl (1,2 N-phenyliminopropyl)phosphonate thus obtained is then dissolved in 2 N sulfuric acid at 40 C. whereupon the compound threo dimethyl [l-(phenylimino)-2-hydroxypropyl]phosphonate is obtained.

Step B: Threo [(l-dimethoxyphosphinyl)-2-hydroxy-2- propyl]-N-phenyl dimethylammonium iodide.-By substituting threo dimethyl [l-(phenylimino)-2-hydroxypropyl]phosphonate for the three di-n-propyl (1-hydroxy-2- aminopropyl)phosphonate of Example 4, Step B, and following the procedure described therein threo [(l-dimethoxyphosphinyl)-2-hydroxy 2 propyl] -N-pheny1 dimethylammonium iodide is obtained.

EXAMPLE 11 Dimethyl (cis-1,2-epoxypropyl)phosphonate Step A: T hreo dimethyl [l-(n-butylthio)-2-acetoxypropylJphosphonate. n-Butylsulfenyl bromide (0.01 mole) is added dropwise to a solution of dimethyl cis-lpropenylphosphonate (0.01 mole) in methylene chloride (20 cc.) at 20 C. to yield cis [(1-dimethoxyphosphinyl)- 1,2-propylene]-n-butylsulfonium bromide. Silver acetate (0.076 mole) in nitromethane cc.) is then added and the reaction mixture is stirred and warmed to 50 C. Concentration of the solvent and extraction of the residue with ether yields, on concentration in vacuo, threo dimethyl l- (n-butylthio -2-acetoxypropyl] phosphonate.

Step B: Threo [(l-dirnethoxyphosphinyl)-1-hydroxy-2- propyl]-di-n-butylsulfonium iodide-By substituting threo dimethyl [l-(n butylthio)-2-acetoxypropyl]phosphonate and n-butyl iodide for the di-n-butyl [l-hydroxy-Z-(ethylthio)propyl]phosphonate and ethyl iodide, recited in Example 5, Step B, and following the the procedure described therein, the compound threo [(1-dimethoxyphosphinyl) -2-acetoxypropyl]-di-n-butylsulfonium iodide is obtained.

Step C: Dimethyl (cis-1,2-epoxypropyl)phosphonate.- By substituting threo [(l-dimethoxyphosphinyl)-1-acetoxy 2 propyl]-di-n-butylsulfonium iodide and sodium chloride for the threo [(1-di-n-butyloxyphosphinyl)-1- hydroxy-2-propyl]diethylsulfonium iodide and silver oxide recited in Example 5, Step C, and following the procedure described therein, the product dimethyl (cis-1,2- epoxypropyDphosphonate is obtained.

EXAMPLE 12 Calcium salt of (cis-1,2-epoxypropyl) phosphonic acid monohydrate Step A: T hreo 1R:2R dimethyl (1-hydroxy-2-aminopropyl)phosphonate.-A solution of racemic threo dimethyl (1 hydroxy 2 aminopropyl)phosphonate (5 mmoles) in acetone (25 cc.) is treated with 1 equivalent of d-lO-camphorsulfonic acid in an equal volume of acetone. The solvent is evaporated hot to the point of near turbidity. The d-lO-camphorsulfonic acid salt of three 1R:2R dimethyl (l-hydroxy-Z-aminopropyl)phosphonate is isolated and dissolved in water, layered with ether and treated with sodium bicarbonate to a pH of 8. Upon extraction of the aqueous phase the resulting ether solution yields, on evaporation, threo 1R:2R dimethyl (l-hydroxy-Z-aminopropyl)phosphonate.

Step B: Threo 1R:2R [(l-dimethoxyphosphinyl)-1-hydroxy-2-propyl]trimethylammonium iodide-By substituting threo 1R:2R dimethyl (l-hydroxy-Z-aminopropyl) phosphonate for the threo di-n-propyl (1-hydroxy-2- aminopropyDphosphonate of Example 4, Step B, and following the procedure described therein the product threo 1R:2R [(l-dimethoxyphosphinyl)-1-hydroxy 2 propyl] trimethylammonium iodide is obtained.

Step C: 1R:2S dimethyl (cis-1,2-epoxypropyl)phosphonate-By substituting threo 1R:2R [(1-dimethoxyphosphinyl)-l-hydroxy 2 propyl]trimethylammonium iodide for the [(1-di-n-propyloxyphosphinyl)-1-hydroxy- 2-propyl]trimethylammonium iodide of Example 4, Step C, and following the procedure described therein the product 1R:2S dimethyl (cis-1,2-epoxypropyl)phosphonate is obtained.

Step D: Calcium salt of (-)-(cis-l,2-epoxypropyl) phosphonic acid monohydrate.A solution of 1R:2S dimethyl (cis-1,2-epoxypropyl)phosphonate (1 mmole) and trimethylchlorosilane (10 cc.) is refluxed for eight hours. The reaction mixture is then extracted with water to yield an aqueous solution of 1R:2S (cis-1,2-ep'oxypropyl)phosphonic acid and the said product is then treated with 1 equivalent of calcium hydroxide and the solution evaporated to yield a crystalline solid identified as the calcium salt of (-)(cis-1,2-epoxypropyl)phosphonic acid monohydrate.

EXAMPLE 13 Dimethyl ester of (cis-1,2-epoxypropyl) phosphonic acid Step A: Threo 1R:2R dimethyl (l-hydroxy-Z-ethylthiopropyl)phosphonate.-A solution of racemic threo dimethyl (l-hydroxy 2 ethylthiopropyl)phosphonate (5 mmoles) in 10 cc. of pyridine is treated with one equivalent of succinic anhydride and heated on a steam bath. After heating for two hours, the pyridine is evaporated and the hemisuccinate extracted with sodium bicarbonate from which it is released by acidification with hydro chloric acid, followed by back-extraction with ether. Evaporation of the solvent yields the hemisuccinate of racemic threo dimethyl l-hydroxy 2 ethylthiopropyl)phosphonate which is then converted to its salt with quinine in acetone solution to yield upon isolation the quinine salt of threo 1R:2R dimethyl (l-succinoyloxy 2 ethylthiopropyl)ph0sphonate. The diastereoisomeric salt thus obtained is treated with dilute sulfuric acid to afford threo 1R:2R dimethyl (1-succinoyloxy-Z-ethylthiopropyl)phosphonate and the intermediate thus obtained is dissolved in dilute sodium carbonate solutions, warmed to 50-60 C., extracted from the aqueous solution with ether and the resulting product isolated by evaporation of the solution to yield threo 1R:2R dimethyl (l-hydroxy-Z-ethylthiopropyl) phosphonate.

Step B: Threo 1R:2R [(1 dimethoxyphosphinyl) 1- hydroxy-Z-propyl]diethylsulfonium iodide.Threo 1R:2R dimethyl [l-hydroxy-2-(ethylthio)propyl]phosphonate (3 mmoles) is dissolved in benzene and the solution treated with ethyl iodide (10 mmoles). The reaction mixture is then warmed at C. for two hours and the benzene evaporated in vacuo to yield threo 1R:2R [(1-dimethoxyphosphinyl) 1 hydroxy 2 propyl]diethylsulfonium iodide.

Step C: Dimethyl ester of (-)(cis-1,2-epoxypropyl)- phosphonic acid.By substituting threo 1R:2R [(1-dimethoxyphosphinyl) 1 hydroxy-Z-propyl] diethylsulfonium iodide for the [(1 dimethoxyphosphinyl)-1-hydroxy-2- propylJdiethylsulfonium iodide recited in Example 5, Step C, and following the procedure described therein, the product dimethyl ester of (cis-1,2-epoxypropyl)phosphonic acid is obtained.

EXAMPLE 14 Di-n-propyl (cis-1,2-epoxypropyl)phosphonate Step A: Racemic threo di-n-propyl (l-hydroxy-Z-cyclohexylaminopropyl)phosphonate.-A solution of 2-(cyclo hexylamino)propionaldehyde (5 millimoles) and dipropylphosphite (5 millimoles) in benzene (5 cc.) is allowed to stand for 18 hours. The solvent is evaporated and the residue distilled to yield racemic threo di-n-propyl (l-hydroxy-2-cyclohexylaminopropyl)-phosphonate.

Step B: Threo [(l-di-n-propyloxyphosphinyl) l hydroxy-2-propyl] N cyclohexyldimethylammonium iodide.By substituting threo di-n-propyl (1 hydroxy-2- cyclohexylaminopropyl)phosphonate for the threo di-npropyl (l-hydroxy-2-aminopropyl)phosphonate of Example 4, Step B, and following the procedure described therein the product threo [(1-di-n-propyloxyphosphinyl)- l-hydroxy-Z-propyl] N cyclohexyldimethylammonium iodide is obtained.

Step C: Di-n-propyl (cis 1,2 epoxypropyl)phosphonate.By substituting threo [(l-di-n-propyloxyphosphinyl)-1-hydroxy 2 propyl]-N-cyclohexyldimethylammoni- 1 7 um iodide for the [(1-di-n-propyloxyphosphinyl)-1-hydroxy-2-propyl]trimethylammonium iodide of Example 4, Step C, and following the procedure described therein the product di-n-propyl (cis-1,2-epoxypropyl)phosphonate is obtained.

EXAMPLE 15 Dimethyl ester of (--)(cis-1,2-epoxypropyl)phosphonic acid Step A: Three dimethyl [l-hydroxy 2 (trifluoroacetoxy) propyl]phosphonate.A solution of the dimethyl ester of 1S:2R (cis-1,2-epoxypropyl)phosphonic acid (0.249 g.) in trifiuoroacetic acid (2 ml.) is allowed to stand at room temperature for 6 hours. Unreacted trifluoroacetic acid is removed in vacuo at room temperature and residue is then flushed with chloroform and benzene to yield 0.447 g. of threo 1S:2S dimethyl [l-hydroxy 2 (trifluoroacetoxy)propyl]phosphonate, A max. 3.04 and 5.59;.

Step B: Threo 1S:2S dimethyl [1-(methanesulfonyloxy)- 2 (trifluoroacetoxy)propyl]phosphonate.-Methanesulfonyl chloride (0.26 ml.) in methylene chloride (0.5 ml.) is added to a stirred solution of threo 1S:2S dimethyl [1- hydroxy 2 (trifluoroacetoxy)propylJphosphonic acid (0.366 g.) in anhydrous methylene chloride (0.5 ml.) and anhydrous pyridine (0.6 ml.) at C. A crystalline solid immediately precipitates out. After standing for 16 hours at 0 C. ice is added to the reaction mixture and the latter is stirred for 45 minutes. The organic layer is separated and the aqueous layer is extracted three times with methylene chloride. The combined organic extracts are then washed with saturated sodium chloride solution, dried over sodium sulfate and evaporated to yield 0.236 g. of threo 1S:2S dimethyl [1 (methanesulfonyloxy)-2- (trifluoroacetoxy)propylJphosphonate. A max. 5.59 and 736 Step C: Dimethyl ester of 1R:2S (cis-1,2-epoxypropyl)phosphonic acid.-To a stirred solution of three 1S:2S dimethyl [l-(methanesulfonyloxy 2 (trifluoroacetoxy)propyl]phosphonate (0.224 g.) in methanol ml.) is added 1.082 N sodium hydroxide (95 ml.). Following the removal of methanol at room temperature in vacuo the residue is saturated with sodium chloride and then extracted three times with ether. Upon evaporation the dried ether extracts yield 0.85 g. of oily product iden tified as dimethyl ester of 1R:2S (cis-l,2-epoxypropyl)phosphonic acid. Upon distillation there is obtained 0.066 g. of dimethyl ester of 1R:2S (cis-1,2- epoirypropyDphosphonic acid [a] +6.1, in methano Upon substituting (sis-1,2-epoxypropyl)phosphon- 1c acid and acetic acid, respectively, for the dimethyl ester of (cis-1,2-epoxypropyl)phosphonic acid and trifiuoroacetic acid recited in Example 15, Step A, and following the procedure described therein there is thus obtamed threo [l-hydroxy 2 (acetoxy)propyl]phosphonic acid which, upon treatment with methanesulfonyl chloride according to the procedure described in Step B of Example 15 alfords lhreo [l-methanesulfonyloxy) 2 (acetoxy) propyl]phosphonic acid, which intermediate, when treated according to the method described in Step C of Example 15 affords the product (ctr-1,2 epox r0 1 hosphonic acid, M.P. 170 C. dec. yp py )p 1335 ...u= 16 (0. 3% H2O) EXAMPLE 1-6 Monobenzylamine salt of (cis-l, 2-epoxypropyl) phosphonic acid A solution of cis-l-propenylphosphonic acid (1 mmole) in water (10 cc.) is treated with pyridine (1 mmole) and the monopyridinium salt of cis-l-propenylphosphonic acid (2 mmoles) thus obtained is added with stirring to 2.5 equivalents of N-bromosuccim'mide and 1 mole equivalent of monopyridinium salt of threo (1-bromo-2-hydroxypropyl)phosphonic acid thus obtained is treated with 3 equivalents of benzylamine to yield the monobenzylamine salt of (cis-1,2-epoxypropyl) phosphonic acid.

EXAMPLE 17 Disodium -(cis-1,2-epoxypropyl) phosphonate A solution of cis-l-propenylphosphonic acid (1 mmole) in water 15 cc. is treated with sodium hydroxide (2 mmoles) and the disodium salt of cis-l-propenylphosphosphonic acid (2 mmoles) thus obtained is added with stirring to 2.5 equivalents of N-bromosuccinimide and 1 equivalent of 10% sulfuric acid until the solution is complete. The solution is complete. The solution of the disodium salt of (1-brorno-2-hydroxypropyl) phosphonate thus obtained is then treated with two equivalents of 1 N sodium hydroxide to yield disodium (cis-l,2-epoxypropyl phosphonate.

By substituting 1 mmole of calcium hydroxide for the 2 moles of sodium hydroxide recited in the foregoing example, the calcium salt of cis-l-propenylphosphonic acid is obtained, which salt upon treatment with N-bromosuccinimide and a 10% sulfuric acid solution according to the method described in in Example 1 affords the calcium salt of (l-bromo-Z-hydroxypropyl)phosphonic acid, and the intermediate thus obtained may then be treated with one equivalent of calcium hydroxide to yield calcium (cis-1,2-e'poxypropyl)phosphonate monohydrate.

EXAMPLE l8 Di-isopropyl ester of 1R:2S (cis-l,2-epoxypropyl) phosphonic acid Step A: Di-isopropyl 2R (Z-chloropropionyl)phosphonate-To a solution of 0.1 mole of 2R chloropropionyh chloride in ml. of anhydrous toluene is added dropwise 0.1 mole of tri-isopropyl phosphite over a period of 30 minutes at 2030 C. After the addition is complete, the mixture is warmed up to 70 C. until the evolution of isopropyl chloride ceases. The solvent is then removed in vacuo and the residue, crude di-isopropyl 2R (2-chloro- 'propionyDphosphonate is used directly in the next step.

Step B: Di-isopropyl 1R:2R (1-hydroxy-2-chloropropyl)phosphonate.-To a stirred suspension of 0.05 mole of lithium tri-tert.-butoxyaluminum hydride in 60 ml. of etherrdiglyme sol-vent mixture (1:1) at -30 C. is added dropwise a solution of 0.045 mole of di-iso propyl 2R (2-chloropropionyl)phosphonate in 30 ml. of ether. The mixture is allowed to stand overnight at 0 C. and the resulting complex is then hydrolyzed and any excess of reagent is destroyed by pouring the reaction mixture onto 150 ml. of 2% acetic acid. Evaporation of the washed and dried ethereal extract alfords di-isopropyl 1R 2R 1-hydroxy'2-chloropropyl)phosphonate.

Step C: Di-isopropyl ester of 1R:2S (sis-1,2- epoxypropyl)phosphonic acid.To a solution of 0.05 mole of di-isopropyl 1R:2R (l-hydroxy-Z-chloropropyl) phosphonate in ml. isopropanol is added 0.05 mole of potassium isopropoxide in 80 ml. of anhydrous isopropanol. The mixture is aged overnight at room temperature and the precipitated potassium chloride is then filtered otr. Evaporation of the filtrate in vacuo afiords the di-isopropyl ester of 1R:2S (cis-1,2-epoxypropyl)phosphonic acid.

EXAMPLE 19 Dimethyl (cis-1,2-epoxypropyl)phosphonate Step A: Dimethyl (O-benzyllactoyl)phosphonate- To a solution of 0.1 mole of o benzyllactoylchloride in 80 ml. of anhydrous ether is added dropwise 0.1 mole of trimethylphosphite over a period of about one hour at room temperature. After the addition of trimethylphosphite the mixture is heated to 30 35 C. until the evolution of methylchloride ceases. The ether is then removed 19 by distillation and the crude dimethyl (O-benzyllactoyl) phosphonate used directly in the next step.

Step B: Dimethyl threo (2-benzyloxy-l-hydroxypropyl)phosphonate.To a solution of 0.1 mole of dimethyl (O-benzyllactoyl)phosphonate in 80 ml. of methanol is added a solution of 0.03 mole of sodium borohydride in methanol with stirring at -10 C. The mixture is aged for hours and the pH of the solution is then adjusted to 6.0 by the dropwise addition of 1 N hydrochloric acid. Upon removal of the solvent in vacuo there is obtained crude dimethyl threo (2 benzyloxy l-hydroxypropyl) phosphonate.

Step C: Dimethyl threo (2-benzyloxy-l-mesyloxypropyl)phosphonate.-Dimethyl threo '(2 benzyloxy-l-hydroxypropyl) phosphonate'(0.1 mole) is dissolved in 160 ml. of anhydrous ether containing 0.105 mole of pyridine. The solution is cooled to 10 C. and 0.1 mole of methanesulfonylchloride is added dropwise while maintaining the temperature between 5 and 10 C. After aging the mixture overnight at room temperature the precipitated pyridine-hydrochloride is filtered off and the solvent is removed in vacuo to yield dimethyl threo (2-benzyloxyl-me syloxypropyl) pho sphon ate.

Step D: Dimethyl (cis-1,2-epoxypropyl)phosphonate. A solution of 0.1 mole dimethyl threo (Z-benzyloxy-lmesyloxypropyl)phosphonate in 250 ml. of dioxane is hydrogenated over a 5% Pd/C (8.0 g.) until the theoretical amount of hydrogen is adsorbed followed by treatment with 0.1 mole of sodium methoxide in 200 ml. of anhydrous methanol. The mixture is then filtered to remove the catalyst and sodium methanesulfonate. The residue is washed with dioxane and the filtrate concentrated in vacuo to yield dimethyl (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE '20' Diethyl Ester of (cis-1,2-epoxypropyl)phosphonate Step A: Benzyl-Z-tosyloxypropionate Benzyl lactate (0.1 mole) is dissolved in 150 ml. of anhydrous benzene containing 0.105 mole of pyridine. The solution is cooled to 10 C. and 0.1 mole of p-toluenesulfonylchloride is added portionwise with stirring and external cooling. After aging the mixture at room temperature for 10 hours the pyridine hydrochloride is filtered off and the solvent is removed in vacuo to yield benzyl-2-tosyloxypropionate.

Step B: 2-Tosyloxypropionic acid A solution of 0.1 mole of crude benzyl-2-tosyloxypropionate in 250 ml. of dioxane is hydrogenated at 25 C. over 5 g. of a 5% palladium-on-charcoal catalyst. After 0.1 mole of hydrogen is absorbed, the catalyst is filtered off and the filtrate is concentrated in vacuo to yield 2-tosyloxypropionic acid.

Step C: 2-Tosyloxypropionylchloride A mixture of 0.1 mole of 2-tosyloxypropionic acid and 0.2 mole of thionyl chloride is warmed at 40 C. for four hours. Upon completion of the reaction excess of thionyl chloride is removed in vacuo and the residual crude 2-tosyloxypropionylchloride is used directly in the next step.

Step D: Diethyl (2-tosyloxypropionyl)phosphonate Method 1: To a solution of 26.25 g. (0.1 mole) of 2-tosyloxypropionylchloride in 60 ml. of anhydrous benzene is added dropwise 16.6 g. (0.1 mole) of triethylphosphite over a period of about 45-50 minutes while maintaining the temperature between 2025 C. by external cooling. After the addition of triethylphosphite, the mixture is aged at 25 C. for one hour and then heated to 50-55 C. until the evolution of ethylchloride ceases. The residual diethyl (2-tosyloxypropionyl)phosphonate thus obtained may be used directly in Step E.

Method 2: To a solution of 69 g. (0.5 mole) of diethyl h'ydrogenphosphite in 500 ml. of anhydrous ether is added 4.6 g. of sodium with stirring and external cooling. After all of the sodium is reacted 52.5 g. of 2-tosyloxypropionylchloride is added portionwise while maintaining the temperature at about 20-25 C. by external cooling. The mixture is then stirred for five hours and the precipitated sodium chloride is filtered 01f. The ether is removed by distillation to yield diethyl (2-tosyloxypropionyl)phosphonate.

Step E: Diethyl threo (1-hydroxy-2-tosyloxypropyl)- phosphonate To a stirred solution of 11.16 g. diethyl (2-tosyloxypropionyl)phosphonate in 45 ml. of methanol is added a solution of 1.2 g. of sodium borohydride in methanol with stirring over 30 minutes at 5-10" C. The stirring is continued for an additional six hours and then 1 N hydrochloric acid is added with cooling and stirring to adjust the pH to 5.5-6. The crude product is obtained after the removal of the solvent in vacuo. Upon removal of the solvent there is obtained crude diethyl threo (l-hydroxy-2-tosyloxypropyl)phosphonate.

Step F: Diethyl ester of (cis-1,2-epoxypropyl) phosphonate Crude diethyl lhreo (1-hydroxy-2-tosyloxypropyl)phosphonate (37.4 g.) is dissolved in 200 ml. of anhydrous dioxane. To this solution is added dropwise at 5 to 0 C., 2.3 g. sodium in 200 ml. of isopropanol. The reaction mixture is aged at 0 C. for 12 hours with stirring and the precipitated sodium p-toluenesulfonate is filtered off and the residue is washed with dioxane and the combined filtrate and washes are concentrated in vacuo to yield crude diethyl ester of (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 21 Dimethyl (cis-l,2-epoxypropyl)phosphonate Step A: Dimethyl threo (l-hydroxy-2-phenoxypropyl)- phosphonate.A solution of 0.2 mole of 2-chloropropionaldehyde and 0.25 mole of sodium phenoxide in 50 cc. of dimethylsulfoxide is stirred for two hours, poured into ice water and extracted with ether. The ether solution is washed with dilute sodium hydroxide and then with water and dried over magnesium sulfate. Concentration of the solvent provides crude 2-phenoxypropionaldehyde which is treated directly with 0.2 mole of dimethyl phosphite and two drops of triethylamine. After standing for 18 hours the reaction mixture is distilled to afford dimethyl threo (1-hydroxy-2-phenoxypropyl) phosphonate.

Step B: Dimethyl (cis-1,'2-epoxypropyl)phosphonate.- A solution of dimethyl threo (l-hydroxy-Z-phenoxypropyl)phosphonate (1 mmole) in methanol (2 cc.) is titrated with 1 N sodium hydroxide using phenolphthalein as the indicator. The total amount of base consumed is 2.0 mmoles. Upon evaporation of the methanol at 50 C., extraction of the residue with ether and concentration of the ether in vacuo, the product obtained is identified as dimethyl (cis-1, 2-epoxypropyl)phosphonate.

EXAMPLE 22 Dimethyl (cis-1,2-epoxypropyl)phosphonate Step A: Dimethyl threo (l-hydroxy-2-azidopropyl)- phosphonate.A solution of, 0.2 mole of 2-chloropropionaldehyde and 0.2 mole of sodium azide in 50 cc. of dimethylsulfoxide is warmed at 50 C. for 2 hours, quenched with water and extracted with ether. Concentration of the ether affords 2-azidopropionaldehyde and the intermediate thus obtained is treated with dimethylphosphite and triethylamine and distilled in the manner described in Example 21 to afford crude dimethyl threo 1-hydroxy-2-azidopropyl)phosphonate.

21 Step 1B: Dimethyl (cis1,2-epoxypropyl)phosphonate.- By substituting dimeth'yl threo (l-hydroxy-Z-azidopropyl)phosphonate for the dimethyl threo (l-hydroxy-Z- phenoxypropyl)phosphonate recited in Example 21, Step B, and following the procedure described therein dimethyl (cis-1,2-epoxypropyl)phosphonate is obtained.

EXAMPLE 23 Diethyl (sis-1,2-epoxypropyl)phosphonate By substituting 3,3-dimethyl-butanoic acid chloride for the methanesulfonyl chloride recited in Example 2, Step B, and following the procedure described therein the compound threo-dieth'yl [1-(3,3-dimethylbutanoyloxy)-2- acetoxypropyl]phosphonate is obtained, which, when treated according to the method described in Step C of that example, yields diethyl (cis-1,2-epoxypropyl)phos phonate.

EXAMPLE 24 Diethyl (cis-1,2-epoxypropyl) phosphonate By substituting chloro diethylphosphite for methanesulfonyl chloride recited in Example 2, Step B, and following the procedure described therein the compound dimethyl three [1 (diethoxyphosphino)-2-acetoxypropyl] phosphonate is obtained, which, when treated according to the method described in Step C of that example, yields diethyl (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 25 Dimethyl (cis-1,2-epoxypropyl)phosphonate A solution of threo dimethyl (1-hydroxy-2-chloropropyl)phosphonate (0.05 mole) in methanol (2 cc.) is treated with mole equivalents of silver acetate in 25 cc. of acetic acid at 5-10 C. for three to four hours, followed by filtration and watering out of the product. The product thus obtained is then extracted with ether and washed neutral with bicarbonate solution to aiford the dimethyl (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 26 Dimethyl (cis-1,2-epoxypropyl) phosphonate Step A: Dimethyl threo [l-[N-(p-toluenesulfonyl) cyclohexylamino]-2-acetoxypropyl]phosphonate.-A so lution of dimethyl cis (1-cyclohexyl-2-methyl 3 aziridinyl)phosphonate (5.0 mmoles) in 20 cc. of acetic acid containing sodium acetate (5.0 mmoles) is refluxed for three hours, cooled, treated with water and extracted with ether. The ether extract is washed free of acid with sodium bicarbonate, dried, and the solvent evaporated to afford dimethyl threo [l-(cyclohexylamino)-2-acetoxypropyl]phosphonate. The said phosphonate is then added to pyridine cc.), treated with p-toluenesulfonyl chloride (5.0 mmoles) and allowed to stand for twelve hours. The reaction product is then treated with water and extracted with ethyl acetate. The organic layer is Washed successively with dilute hydrochloric acid and sodium bicarbonate solution, dried over magnesium sulfate and concentrated to yield dimethyl threo [1-[N-(p-toluenesulfonyl) cyclohexylamino] -2-acetoxypropyl] phosphonate.

Step B; Dimethyl (cis-1,2-epoxypropyl)phosphonate. By substituting dimethyl threo [1-[N-(p-toluenesulfonyl) cyclohexylamino] 2 acetoxypropyl]phosphonate for the [(1-di-n-propyloxyphosphinyl)-1-hydroxy 2 propyl]trimethylammonium iodide of Example 4, Step C, and following the procedure described therein, the product dimethyl (cis-1,2-epoxypropyl)phosphonate is obtained.

EXAMPDE 27 Dimethyl (cis-l,2-epoxypropyl)phosphonate Step A: Dimethyl threo (1,2-dihydroxypropyl)phosphonate-A solution of 2-hydroxypropionaldehyde (l0 mmoles) in benzene (5.0 cc.) is treated with dimethylphosphite (10 mmoles) and two drops of triethylamine and allowed to stand for hours. The organic phase is washed free of triethylamine with dilute hydrochloric acid followed by a Washing with sodium bicarbonate and water. The resulting solution is then dried over magnesium sulfate and the solvent evaporated to yield dimethyl threo 1,Z-dihydroxypropyl)phosphonate.

Step B: Dimethyl (cis-1,2-epoxypropyl)phosphonate-- A solution of dimethyl threo (1,2-dihydroxypropyl)phosphonate (5.0 mmoles) in anhydrous chloroform (35 cc.) is stirred at 50 C. with phosphorous pentoxide (1.0 g.) for three hours. The solution is then decanted, washed with sodium bicarbonate solution and concentrated to yield dimethyl (cis-l,2-epoxypropyl)phosphonate.

EXAMPLE 28 Diethyl (cis-1,2-epoxypropy1)phosphonate A solution of dimethyl threo (l-hydroxy-Z-acetoxypropyl)phosphonate (5.0 mmoles) in 25 cc. of dimethoxyethane is treated with potassium tert.-butoxide (5.0 mmoles) at 30 C. for five hours. The reaction mixture is then filtered and the organic phase washed with water, dried over magnesium sulfate and concentrated to yield diethyl (cis-1,2-epoxypropyl)phosphonate.

EXAMPLE 29 Disodium salt of (cz's-1,2-epoxypropyl)phosphonic acid A solution of cis-l-propenylphosphonic acid (0.1 mole) in 40 cc. of acetic acid is treated with peracetic acid (0.1 mole) at 25 C. After six hours the reaction mixture is treated with sodium bisulfite (0.01 mole), concentrated to dryness and flushed with benzene. The residue is dissolved in pyridine (30 cc.) and treated with thionyl chloride (0.3 mole) and allowed to stand for 16 hours. Upon removal of the major portion of the volatiles under reduced pressure the residue is treated with sodium hydroxide (0.5 mole) in 50 cc. of water. After standing for one hour, there is obtained a solid product identified as the disodium salt of (cis-1,2-epoxypropyl)phosphonic acid.

EXAMPLE 30 Disodium salt of (sis-1,2-epoxypropyl)phosphonic acid Threo (2-acetoxy 1 hydroxypropyl)phosphonic acid (0.05 moles) is dissolved in 20 cc. of hexafiuoroacetone containing a catalytic amount of para-toluenesulfonic acid (20 cc.) and allowed to stand for 12 hours. Excess hexafluoroacetone is removed in vacuo and the residue treated with 0.2 moles of sodium hydroxide in 20 cc. of water to yield the disodium salt of (cis 1,2 epoxypropyl)phosphonic acid.

EXAMPLE 31 Calcium i (Cis-1,2-epoxypropyl) phosphonate Step A: Threo (1-chloro-2-hydroxypropyl)-phosphonic acid.-(a) To a stirred solution of cis-l-propenylphosphonic acid (0.599 g., 0.00491 mole) in water (2 ml.) cooled in an ice-water bath, is added t-butyl hypochlorite (0.585 ml., 0.00491 mole). After one-half hour at approximately 0 C. the cooling bath is removed and within ten minutes the heterogeneous reaction mixture becomes homogeneous, although occasional cooling is necessary to control the exothermic nature of the reaction. After a total period of four hours the reaction mixture is evaporated to give a semi-crystalline material which is slurried in ether and filtered to afford (i) threo (1-chloro-2- hydroxypropyl)phosphonic acid (0.610 g., 71.3%), m.p. 149-152 C.

(b) To a stirred solution of cz's-l-propenylphosphonic acid (1.220 g., 0.01 mole) in Water (2.5 ml.) cooled in an ice-water bath, is added sodium hypochlorite (0.01006 mole, 5%) at such a rate (over approximately a tenminute period) that the temperature of the reaction mixture is maintained at 10-15" C., after which the cooling bath is removed and the solution stirred for 1.5 hours. In order to remove excess hypochlorite, tertiary-'butanol (10 ml.) is added to the solution and the latter evaporated until it is free from tertiary-butanol. The aqueous solution is passed through a column packed with 60 ml. of a polystyrene nuclear sulfonic acid ion exchange resin (Dowex 50 (H+)) followed by the addition of water (180 ml.). The combined eluates were freeze-dried to afford a crystalline material which is taken up in cold acetonitrile (5 ml.), filtered and washed with more cold acetonitrile (5 ml.) to yield (i) threo (l-chloro-2-hydroxypropyl) phosphonic acid (1.492 g., 85.5% m.p. 15l153 C.

Step B: Calcium (cis-1,2-epoxypropyl)phosphonate.-To a stirred solution of (i) threo (1-chloro-2- hydroxypropyl)phosphonic acid (0.246 g., 0.00141 mole) in water (0.5 ml.) cooled in an ice-water bath, is added approximately 16 N sodium hydroxide (1.1 ml., 0.0176 mole). After standing for approximately 25 minutes at room temperature the reaction mixture is diluted with water (0.7 ml.), cooled to approximately C. and then adjusted to pH 8-9 by the dropwise addition of concentrated hydrochloric acid. To the clear alkaline solution at room temperature is added calcium acetate monohydrate (0.249 g., 0.00141 mole). The reaction mixture is then seeded with calcium (i) (cis-1,2-epoxypropyl)phosphonate, scratched and the solution stirred for one-half hour. The solid is collected by filtration, washed with water (12 m1.) and finally dried at 40 C. in vacuo overnight to furnish calcium (i) (cis-1,2-epoxypropyl)phosphonate (0.153 g., 61.5%).

EXAMPLE 32 Disodium salt of (cis-1,Z-epoxypropyl)phosphonic acid Step A: Threo (l-chloro-2-hydroxypropylphosphonic acid.-To a stirred solution of (i) threo (lchloro-Z-hydroxypropyl)phosphonic acid (4.363 g., 0.025 mole) in water (5 ml.) is added a solution of alphaphenethylamine (3.03 g., 0.025 mole) in isopropanol (5 ml.). Evaporation of the clear reaction mixture affords a solid (m.p. 145-156 C.) which on crystallization from an 80% solution of isopropanol in the presence of monoalpha-phenethylammonium (+)thre0 (1-chloro-2- hydroxypropyl)phosphonate as seed, furnishes (2.625 g., 71%) of a solid material melting at 173176 C. Upon crystallization the mother liquor twice furnishes an additional 0.274 g. amount of material thus increasing the total yield of product to 78.5%. Upon further crystallization the solid melts at 174-177 C., a sample (1.660 g.) of which is dissolved in water (15 ml.) and then passed through a column packed with 25 ml. of a polystyrene nuclear sulfonic acid ion exchange resin (Dowex 50 (H*)) followed by the addition of water (75 ml.). The combined eluates are then freeze-dried to afford a partially crystalline material which, upon addition of ether followed by evaporation, yields a completely solid material identified as threo (1-chloro-2-hydroxypropyl) phosphonic acid, wt. 0.975 g., mp. 106-107 C., ,,=+19.03 (c.=3.415; H O). Crystallization from ether raised the melting point of the threo (1-chloro-2-hydroxypropyl)phosphonic acid thus obtained to 107-108 C.

Step B: Disodium salt of (cis-l,2-epoxypropyl)- phosphonic acid-To a stirred solution of threo (1- chloro-2-hydroxypropyl)phosphonic acid (0.229 g.) in water (0.5 ml.), cooled in an ice-water bath, is added 16 N sodium hydroxide (1.06 ml.). After removal of the cooling bath the reaction mixture is stirred for 25 minutes, again cooled, diluted with water (0.7 ml.) and the pH of the solution adjusted to pH 8-9 by the dropwise addition of concentrated hydrochloric acid. The reaction mixture is then freeze-dried to afford the disodium salt of (cis-1,2-epoxypropyl)phosphonic acid contaminated with sodium chloride, the rotation of which was determined without removal of the contamination as:

l-105m (c.=4.76, H 0).

24 EXAMPLE 33 Dibenzyl (cisand trans-1,2-epoxypropyl)phosphonate Step A: Threo and erythro dibenzyl (l-hydroxy-Z- chloropropyl)phosphonate.--Freshly distilled 2 chloropropionaldehyde (2.78 g., 0.03 mole) and dibenzylphosphite (7.86 g.) are mixed and heated in an oil bath at 65 C. for 66 hours. The product thus obtained is identified as an isomeric mixture of the threo and erythro isomers of dibenzyl (1-hydroxy-2-clfloropropyl)-phosphonate.

Step B: Dibenzyl (cisand trans-1,2-epoxypropyl)phosphonate.The mixture of three and erythro dibenzyl (1- hydroxy-Z-chloropropyl)phosphonate (3.54 g., 0.01 mole) obtained according to Step A is stirred with a solution of 85% potassium hydroxide (0.66 g., 0.01 mole) in 25 ml. of water for 7.5 hours. The pH of the mixture changes from 11.81 to 9.25 whereupon additional potassium hydroxide (0.07 g.) is added to effect a pH of 10.9 and the mixture is then stirred overnight to afford a solution having a pH of 8. The mixture is then extracted with two 25 ml. portions of chloroform, washed with sodium bicarbonate, dried over magnesium sulfate and evaporated to dryness in vacuo to afford 2.25 g. of an oily product which when subjected to infra red analysis, indicated the presence of epoxide (8 and some benzyl alcohol. The product (1.6 g.) is then subjected to dry column chromatography on a column made of g. silica gel and a chromatogram is developed by a mixture of 88% chloroform and 12% of acetone (by volume). Upon evaporating a fraction to dryness and analyzing by nuclear magnetic resonance the presence of dibenzyl (trans-1,2-epoxypropyl)phosphonate and dibenzyl (cis-1,2-epoxypropyl) phosphonate in a ratio of 4:1 is confirmed.

Nuclear Magnetic Resonance Data:

trans, twin doublet 6 2.72. J: 32 c.p.s., 2.8 c.p.s. cis,

doublet J 4 c.p.s.

C H singlet 7.37 p.p.m.

'C H OH OP: doublet 5.1 p.p.m. J: 8.5 c.p.s.

CH trans, twin doublet 6 1.27 p.p.m. J: 7 c.p.s., 1.5 c.p.s.

cis, doublet 6=1.55 p.p.m. J: 5.5 c.p.s.

Racemic and 1R:2S (cis-'1,2-epoxypropyl)phosphonic acid and its corresponding salts and ester derivatives (I) may be obtained simply by substituting the ap propriate starting materials for those described in Example l, Steps A, B, and C. Thus, for example, by substituting a suitable phosphite, an appropriately substituted aldehyde and the desired base for the dimethyl phosphite, 2-chloropropionaldehyde and the sodium hydroxide reagent recited in Example 1, Steps A, B and C and following the procedure described therein all of the 1,2-disubstituted n-propylphosphonate intermediates identified as -IIb, infra, the desired (cis-1,2-epoxypropyl)phosphonic acid product and the salts and ester derivatives thereof may be obtained. The following equation illustrates the reaction of Example 1, Steps A, B and C and, in conjunction with Table I, infra, describe the several varieties of phosphites and propionaldehdye starting materials which may be employed in the process of this invention and the 1,2-disubstituted n-propylphosphonate intermediates (IIb, infra), (cis-1,2-epoxypropyl)phosphonic acid product 25 (Ic) and corresponding phosphonate analogs (Ib and Id) derived therefrom:

O O om-onx -ono 31 03 om-cn-on-ixom,

IIb Basel The products of this invention can be administered in a wide -variety of therapeutic dosages in conventional vehicles as, for example, by oral administration in the form of a capsule or table or in a liquid solution or suspension. Suitable formulations may include diluents, granulating agents, preservatives, binders, flavoring agents and coating agents which are well known to those skilled in this particular art and the dosage of the products may be varied over a wide range as, for example, in the range of from about 500 mg. to about 4.0 g. per day of active ingredient per adult for the symptomatic adjustment of 1b the dosage to the patient to be treated.

Alternatively, the instant products (I) may be adminy y l istered parenterally by injection in a sterile excipient and 0 for this purpose it is most desirable to employ a salt of C CH T 0H (cis-1,2-epoxypropyl)phosphonic acid which is soluble in 37 h the liquid vehicle.

0 It is also within the scope of this invention to comfi bine two or more of the instant products in a unit dosage Hydroxidel form or to combine one or more of the instant products 0 OM with other known antibacterial agents. T The following examples illustrate the preparation of a E representative dosage; it being understood that other salts 0 0M 2 of (cis-l,2-epoxypropyl)phosphonic acid and other phar- Id maceutical vehicles may be substituted for the active in- TABLE I Example OR X M M Base a4 Q --OSO2C2H5 K K Pyridine.

Br Ca- Do.

36 I Na Na NaOH.

37 -0CHs N Na Na NaOH.

OC-CH:CH3

38 -CH(CH )a (l) Mg- AgO -OCLCH2OF;

39 0CzHs 0 -Mg NflOH:

40 -OOHs i) Li Ll AgO.

-OO-CHz-CCL;

41 OCH: 0 -Cd NBOCQH 42 L1 Li Pyridine;

43 0(CHz) CH 9 K K NaOCH:

44 (CHz)zCHs (H) K K Pyridine:

--0C--CH 45 0Ll -0S0 CH Na Na NaOH.

27 gredient and excipients recited therein to obtain other suitable active dosage forms:

EXAMPLE 46 Dry-filled capsule containing 330 mg. of active ingredient per capsule Capsule size No. 475

The anhydrous disodium (i) (sis-1,2-epoxypropyl) phosphonate is reduced to a N0. 60 powder and then lactose and magnesium stearate are passed through a No. 60 bolting cloth onto the powder and the combined ingredients admixed for 10 minutes. After a uniform blend is obtained the solids are milled to a particle size of less than 10 microns and then filled into No. dry-gelatin capsules.

By substituting 352.5 mg. of calcium (i) (cis-1,2- epoxypropyl)phosphonate monohydrate for the anhydrous disodium (i) (cis-1,2-epoxypropyl)phosphonate of the above example and otherwise following the procedure described therein a similar dry-filled capsule suitable for oral administration is obtained.

EXAMPLE 47 Tablets containing 352.5 mg. of active ingredient per tablet Per tablet, mg. Calcium (i) (cis-1,2-epoxypr0pyl)phosphonate 352.5

Dicalcium phosphate 180 Lactose U.S.P. 179.5 Cornstarch a 80 Magnesium stearate 8 EXAMPLE 48 Oral liquid containing 132 g. of active ingredient Per 1000 ml. Disodium (i) (cis-1,2-epoxypropyl)phosphonate gm 132.0 Sucrose Em 600.0 Glucose gm 250.0 Citric Acid gm 13.0 Sodium benzoate cm 1.0 Concentrated Orange Oil ml 0.2

Purified water, U.S.P. to make 1000.0 ml.

The sucrose and glucose are dissolved in about 400 ml. of water with heating. The solution is then cooled and citric acid, sodium benzoate and orange oil are added. The solution is brought to a volume of about 900 ml. with water and disodium (cis-1,2epoxypropyl)phospho mate is added. The solution is filtered and brought to a volume of 1000 ml.

What is claimed is:

1. A compound of the formula where R is hydrogen or loweralkyl, one of X and X represents lower alkanesulfonyloxy, arylsulfonyloxy, alkarylsulfonyloxy or aralkylsulfonyloxy, and the other of X and X represents hydroxy, loweralkanoyloxy or trihalomethyl loweralkanoyloxy.

2. A compound of Claim 1 wherein R is lower alkyl.

3. The compound of Claim 1 wherein R is lower alkyl, X is lower alkanesulfonyloxy and X is trifluoroacetoxy.

4. The compound of Claim 3 wherein R is methyl and X is methanesulfonyloxy.

5. The compound of Claim 1 wherein X is hydroxy and X is lower alkanesulfonyloxy or alkarylsulfonyloxy.

6. The compound of Claim 1 wherein X is lower alkanesulfonyloxy and X is lower alkanoyloxy.

7. Threo 1S:2S dimethyl [1-(methanesu1fonyloxy)-2- (trifiuoroacetoxy)propyl]phosphonate.

References Cited UNITED STATES PATENTS 2,593,213 4/ 1952 Stiles 260970 X 2,579,810 12/1951 Fields 260970 X 3,501,556 3/1970 Weil et al 260970 X 3,654,151 4/1972 King et al. 260-456 R OTHER REFERENCES Kosoloznoif: Organophosphorus Compounds, pp.

LEON ZITVER, Primary Examiner N. MORGENSTERN, Assistant Examiner US. Cl. X.R.

' 260--239 EP, 327 E, 348 R, 348.6, 456 P, 501.21, 502.4 R, 

